Mold drawing device for molding machines



Oct. 2, 1951 H. J ROTHSCHILD 2,569,580

MOLD DRAWING DEVICE FOR MOLDINGMACHINES Filed Feb. 10, 1949 2 Sheets- -Sheet 1 INVENTQIL: Hcuysjalwb ROihsc/vi/cl.

H. J. ROTHSCHILD MOLD DRAWING DEVICE FOR MOLDING MACHINES 2 Sheets-Sheet 2 Filed Feb. 10, 1949 gar/ j A. a?

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Fig-2 dmkw ATT LN E35 Patented Oct. 2, 1951 MOLD DRAWING DEVICE FOR MOLDING MACHINES Hans Jakob Rothschild, Schafihausen, Switzerland, assignor to Georg Fischer Aktiengesellschaft, Schaffhausen, Switzerland, a company of Switzerland Application February 10, 1949, Serial No. 75,703 In Switzerland December 9, 1948 This invention relates to a mold drawing device for molding machines of the jolt, squeeze and draw type.

In operating molding machines of the above described type it is very important to control the speed of the drawing motion in such a Way that at the very beginning and only over a short distance of the drawing motion the mold is drawn from the pattern at a very reduced speed, compared with the normal speed at which the operation is to be continued. I

.Molding machines with pneumatically actuated mold drawing devices are known. In these machines the controlling of the drawing speed is mostly accomplished by 'means of interchangeable .cams or sliding crank blocks. The changing or altering of these regulating means is often complicated and time consuming.

The principal object. of this invention is to provide regulating means for the drawing speed of the mold drawing cylinder by reducing the flow of a pressure medium through the bore of a vertically displaceable regulating means.

Another object of the invention is to provide means for altering the vertical position of the .rgulating means by means of a crank pin.

-. Another object of the invention is to provide check valve means in the vertically adjustable regulating means for controlling the drawing speed during the rising and lowering motion.

An embodiment of the molding machine according to the present invention is illustrated by way of an example in the accompanying drawing, in which Fig. 1 is a vertical sectional view of the molding machine, a part thereof being shown in side elevation,

Fig. 2 is a sectional view of the regulating means; and Fig. 3is a detailed sectional view taken on the line II-II of Fig. 2.

. In Fig. 1 are shown the molding machine standard I, with the laterally rockable head piece 6, and the vertically adjustable press plate 5, the molding machine table 2 with the mold containing flask 3, and the pattern 4. With the mold :drawing cylinder 1 are rigidly connected the supporting frame 8, the adjustable members 9 and the mold lifting pins ill. The mold drawing cylinder 1 is vertically slidable on the mold drawing piston II which is securelyconnected with the molding machine standard I. Screwed into the upper end of the mold drawing piston I l is the regulating pin l2, the diameter of which is slightly smaller than the diameter of the bore 2 Claims. (Cl. 22-48) 2 33 in the regulating sleeve H. The upper end of the regulating pin I2 may be pointed or conical. In the intermediate piece 20 between the two sections-of the drawing cylinder 1 is the vertically slidable regulating sleeve l4. Air supply conduit I! leads into the pilot valve [8 and conduit 19 leads from the pilot valve l8 into the upper end of the space l3, which in service is to be filled with oil. The exhaust conduit 34 leads from the pilot valve l8 into the atmosphere. Rigidly connected with the machine standard I is the abutment 35'which serves as end stop for the maximum lengthof the drawing stroke.

In Figs. 2 and 3 are shown the details of the regulating means. The intermediate piece 20 houses the axle [5 with the crank pin 2| which rests in the groove 22 of the regulating sleeve l4. On the axle l5-is the hand wheel axially slidable l 6 with the key way 28 which serves as guide for the key 29 in the axle 15. The hand wheel I6 is pressed against the face 31 of the intermediate piece 20 by means of the spring 21 which is secured to the axle I5 by means of the washer 25 and the nut 26.

The face 31 of the intermediate piece 20 is in the above case provided with eight index holes 23 for the index pin 24 fixed in the hub of the hand whee] IS. The outside diameter of the hub of the handwheel I6 is fitted with a scale 36.

The regulating sleeve M has one bore 33 which isslightly larger in diameter than the regulating'pin l2. In the upper enlarged ends of two side bores 30 are check valve balls 3| which are secured in their bores by means of a securing wire 32.

The above described mold lifting device according to the Figs. 1. 2 and 3 operates as follows:

The Figs. 2 and 3 show the condition where the crank pin 2| of the axle I5 rests in its lowermost position and where also accordingly the index pin 24 rests in the lowermost index hole 23 which is drawn hatched in Fig; 3. In this position of the crank pin 2| the regulating sleeve I l rests also in its lowermost positionwhere the distance up to which the regulating pin l2 enters into the bore 33 reaches its maximum.

For initiating the drawing operation, which means the lifting-01f of the mold 3 from the pattern 4, the pilot valve l 8 is turned to such a position as to allow the air to enter from the supply conduit I! through the conduit I9 into the upper end of the drawing cylinder 1. The whole space l3 which is not occupied by the drawing piston II is filled with oil. If compressed air is applied on the surface of the oil level in space I3 then the oil is forced downwards from the space l3 through the annular passage which is formed by the clearance between the regulating pin I2 and the bore 33 in the regulating sleeve M. The oil is forced to-flow only through .this;annular passage asthetwo side bores 3|]:remain closed because of the check valve balls 3| which do not allow the flow of oil in downwards direction. Due to the very limited area of said annular passage, the initial drawing speed will be' very 'reduced as long as the regulating pin l2 projects into the bore 33. As soon as the regulatinggsleeve [4 has reached such a heightabove-the drawing piston II that the regulatingpin l2 .leaveszthe bore 33, then the reduced initial drawing speed changes. to a regular drawing speed, which is maintained until the drawing pistoni'l. touohesthe abutment 35.

When the drawing operation is completed, which means, that ther-mold 3 has been taken awayfromthe lifting pins [0, then thepilottvalve 1:8 is turned to such a positionasto allowithe .air from the space I3 and the conduit 19 to be exhausted through the conduit 34 into the-atmos- ;;phere. By their own Weight the drawing cylinder *7, together with the .parts 8, 9 and Ill-begin to descend and this descending movement keeps on until the! drawing cylinder 1 has reached its lowermost position, as indicated-in Figs. 1- and 2. During-this descending movementtheoil inthe drawing cylinder ,1 irises'from the lowerwspace above the drawing piston H through the 'bore 33 as well as throughzthe two side bores 30-of the :regulating sleeve l4 into the upper space 13. By

theflowing-oil the check'valve -balls 3| in the I.

=side bores-30 are lifted'until they touch the securing wire 32. Because of theiact that the oil flowing through all three bores, 30 and '33, of the-regu1atingsleeve M, the descending speed of .the drawing'cylinder exceeds the maximum speed of the 1 ascending motion Y of -.said drawing cylinder.

If it is desirable to change the length of time during which the drawing speed is to-be-reduced before assuming itsnormal drawing -speed,:the

rfollo'wing is done:

The -hand wheel 16 with thedndex-pin :24 is pulledaway iromthe face3l against the pressure of the spring" 21- untilthe index pin 24 staysoutsid ofits index hole 23. -Now .theihand.wheel J6 is turned to such an extent that the-index :pin 24 rests above one of the other index holes-23. As soonas 'the'handwheel IBis released'the index pin 24, by action of :the spring 21, enters into this new index hole. This positioning -.of the :hand wheel It may be accomplished by Job- "serving the graduation '36 on the 'hub of the handwheel l 6. The-key!!! imthe axlel5'is slide- -able-in'the keywayfitl of .the-handawheel l 6 :and when'the latter is'iturned the -:axle 1'5 with the -crankpin 2! is -tu-rned-as'well. By the movement-ofthe crank pin -2I, which-restsiinthe annular groove 22 of'theregulating sleeve M, the latterismoved vertically: i. e.- theregulatingi Din I-2 enters "to a lesser :depth into the :bore 33 of the regulating sleeve :M. In -a subsequent draw- =ing operation :the lengthof time during which the reduced initial drawing-speed :is: maintained will be shorter than in the previous setting of the regulating sleeve 14.

The utilization of a mold drawing device, according to the above described invention, allows theregulation of theinitial drawingrspeed in a .simple and accurate mannervwithout interrupting the operation of the molding machine. This can be accomplished irrespective of the weight and form of the mold.

:The'end of the'regulating pin may be conical in order to obtain a smooth and shockless change=over from 'the reduced initial drawing speed :tothe normal drawing speed.

I-claim:

1. In 'a molding machine of the jolt, squeeze .and draw type, a drawing device comprising, inzcombination with a molding machine standard, a lifting piston firmly connected with said standard, a drawing cylinder enclosing said piston and vertically slida-ble thereon, and pin-supporting rneans connected {to said (cylinder and inovable ltherewith; .a regulating sleeve :located within said cylinder and having aqborerpassage :formed therein, a regulating pincarried:by:;said

. LDlStOll and ienteringsaidgbore; passage in .the low- =ermost1positionof said cylinder, and means. connectingcsaid sleeve with said cylinder and: selectively shifting said sleeve into. one ;of. a plurality of vertically displaced positions.

-:2.:In.a molding machine of :the 'jolt,r-squeeze and draw type, a drawing :devicacomprising, .in combination with r a molding machine standard, :alifting piston-zfirmly connected with said standard, :a drawing cylinder enclosing said piston-and vertically sli'dable thereon, and pin-supporting imeans .connected to said .cylinder and ;movable ztherewith; .aregulating'sleeve located within said cylinder and having a bore passage 'formedthere- .a regulating .pin .carried by said piston and enteringrsaidrbore passagein the lowermost posi- .-:tion of said cylinder, said sleeve having: a groove :formed therein, a crank spin located in "said groove,:anuaxletcarrying saidcrank pin, a hand awheel.iaxially slidable upon said axle androtatrable therewith, aniintermediate piececarrie'd by said cylinder and having apluralityof index'holes 'formed therein, and ameans :connected with: said thand lwheel LfOI' I selectively engaging one of nsai'd index holes, whereby 'the-tturning ofsaid hand wheel shifts said-sleeve into one s of :a plurality of vertically displaced positions.

HANS JAKOB' ROTHSCHIED.

REFERENCES CITED The following references are of record .in the filc of'this-patent:

-.U-NITED STATES --PA-TENTS Num-er Name Date 961,702 Lewis June"-14,-l'9 10 1,931,902 Oyster 'Octr24, 1933 2,376,203 *Stemmler May"l5,"1'945 2,438,218 "Johnston "Mar.23, '19'4'8 .FOREIGN PATENTS fNumber Country Date 350,020 -.,Great Britain .June- 8, 1931 .358 ;781 Great Britain -.O.ct. 15,1931 

